Radar apparatus and radar signal processing method

ABSTRACT

A radar apparatus and a radar signal processing method are provided. The radar apparatus includes a plurality of transmitting antennas, a plurality of non-uniformly and linearly deployed receiving antennas, a sensor signal processor configured to calculate target range-Doppler data from signals input from a receiving antenna arrangement according to virtual antennas while sequentially driving the plurality of transmitting antennas, and a target position calculator configured to calculate position data of a target from arrangement mapped data obtained by rearranging the virtual antenna-specific range-Doppler data output from the sensor signal processor with reference to antenna configuration related information.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of U.S. application Ser.No. 16/373,636, filed Apr. 3, 2020 (now pending), which claims priorityfrom Korean Patent Application No. 10-2019-0002485, filed on Jan. 8,2019, in the Korean Intellectual Property Office, the disclosure ofwhich is incorporated herein by reference in its entirety.

BACKGROUND 1. Field

The following description relates to a radar technology and moreparticularly, to a radar apparatus having multiple transmitting antennasand multiple receiving antennas and a radar signal processing method.

2. Description of Related Art

There is a known technique for increasing the spatial resolution of aradar apparatus in which multiple transmitting antennas and multiplereceiving antennas are deployed by sequentially driving the transmittingantennas and the receiving antennas.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

The following description relates to a radar apparatus which has ahigher spatial resolution using the same number of antennas.

The following description relates to a technical solution which makes itpossible for a radar apparatus to have a plurality of differentcharacteristics while having a fixed antenna arrangement.

In one general aspect, a radar apparatus includes a plurality oftransmitting antennas and a plurality of receiving antennas which arenon-uniformly and linearly deployed. While the transmitting antennas aresequentially driven, signals input from the receiving antennas areprocessed in consideration of the non-uniform linear arrangement of thereceiving antennas so that position data of a target is calculated.

In an additional aspect, while the transmitting antennas aresequentially driven, radar signals are received from the receivingantennas and processed. Therefore, it is possible to implement a greaternumber of virtual antennas or virtual receiving channels than physicalantennas, and wide coverage is effectively achieved by a non-uniformlinear arrangement of the virtual antennas or the virtual receivingchannels.

In an additional aspect, a plurality of antenna arrangements areintended by designing antennas to be driven and designing a drivingsequence of the antennas in a physically fixed antenna arrangement. Itis possible to detect and track a plurality of different targets withone physical radar by selectively applying a plurality of antennaarrangements.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an overall configuration of a radar apparatus according toan exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of one transmittingand receiving channel of a sensor signal processor according to anexemplary embodiment of the present invention.

FIGS. 3A, 3B, 4A and 4B show exemplary embodiments of a non-uniformlinear arrangement of antennas.

FIG. 5 is a block diagram showing a configuration of a radar apparatusaccording to an exemplary embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a sensor signalprocessor which processes a signal received by one virtual antennaaccording to an exemplary embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a target positioncalculator according to an exemplary embodiment of the presentinvention.

FIG. 8 shows an example of an arrangement of virtual antennas and onerow extracted from the arrangement.

FIG. 9 is a block diagram showing a configuration of a target positioncalculator according to another exemplary embodiment of the presentinvention.

FIG. 10 is a diagram illustrating another example of antennaconfiguration related information.

FIG. 11 is a block diagram showing a configuration of an angularposition calculator according to an exemplary embodiment of the presentinvention.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The above-described and additional aspects of the present invention willbecome more apparent from exemplary embodiments which will be describedwith reference to the accompanying drawings. It is understood thatelements of each embodiment may be combined in a variety of ways withinthe embodiment unless otherwise indicated or contradictory.

FIG. 1 shows an overall configuration of a radar apparatus according toan exemplary embodiment of the present invention. The radar apparatusaccording to an exemplary embodiment of the present invention includes aplurality of radar sensors 10-1, 10-2, . . . , and 10-n and a controller70 which controls the radar sensors 10-1, 10-2, . . . , and 10-n in anintegrated manner. Each of the radar sensors 10-1, 10-2, . . . , and10-n has I transmitting channels and m receiving channels and isconnected to I transmitting antennas and m receiving antennas. As shownin the drawing, each antenna 30 may include a feeding line 31 and aplurality of patches 33 arranged along the feeding line 31. When thepatches 33 having different or identical sizes are arranged along thefeeding line 31, a directional characteristic of the individual antenna30 may be designed by adjusting intervals between the patches 33.According to an exemplary embodiment of the present invention, the radarsensors 10-1, 10-2, . . . , and 10- may be a commercialized singlefrequency-modulated continuous wave (FMCW) radar sensor semiconductor.

FIG. 2 is a block diagram showing a configuration of one transmittingand receiving channel of a radar sensor 10 according to an exemplaryembodiment of the present invention. The transmitting channel includes aramp generator 193 for controlling an FMCW oscillation frequency, avariable oscillator 131, and a power amplifier 111. The receivingchannel includes a low-noise amplifier 113, a down converter 135, anintermediate frequency processor 191, and an analog-to-digital converter(ADC) 150. A signal processor 170 controls the radar sensor 10 accordingto internal firmware and includes a dedicated circuit, a microprocessor,and a digital signal processor. The radar sensor 10 according to anexemplary embodiment of the present invention has four receivingchannels and three transmitting channels in a single chip. The radarsensor 10 is connected to an external controller through a serialinterface and thus is programmable. The signal processor 170 controlsthe variable oscillator 131 to generate an FMCW radar signal. Also, thesignal processor 170 may process a digital radar signal output from theADC 150 by programming the internal microprocessor and digital signalprocessor.

According to an aspect, the radar apparatus is connected to an antennaarrangement including a plurality of transmitting antennas and aplurality of receiving antennas. According to an aspect, the pluralityof transmitting antennas and/or the plurality of receiving antennas arenon-uniformly and linearly deployed. As an example, the plurality oftransmitting antennas may be non-uniformly and linearly deployed, andthe plurality of receiving antennas may be uniformly and linearlydeployed. As another example, the plurality of transmitting antennas maybe uniformly and linearly deployed, and the plurality of receivingantennas may be non-uniformly and linearly deployed. As another example,all the plurality of transmitting antennas and all the plurality ofreceiving antennas may be separately, non-uniformly, and linearlydeployed.

In “non-uniformly and linearly deployed,” “linearly deployed” denotesthat multiple antennas are deployed along a straight line or a curvedline. Also, “non-uniformly deployed” denotes that intervals betweenantennas are not regular. The present invention does not preclude atwo-dimensional arrangement. For example, when transmitting antennas arealternately deployed in two lines and receiving antennas are linearlydeployed, a virtual antenna arrangement may have a higher density. Inother words, the term “non-uniformly and linearly deployed” is definedto denote an arrangement of antennas including a part in which antennasare linearly deployed at irregular intervals. Transmitting antennas andreceiving antennas may be deployed so that a line of the transmittingantennas and a line of the receiving antennas cross each other.

Korean Unexamined Patent Application No. 10-2018-0035463 filed by thepresent applicant on Mar. 27, 2018 discloses examples in which antennasare non-uniformly and linearly deployed. FIGS. 3 and 4 show exemplaryembodiments of a non-uniform linear arrangement of antennas disclosed inthe earlier application.

FIG. 3A shows physical arrangements of transmitting antennas andreceiving antennas according to an exemplary embodiment of the presentinvention. In the exemplary embodiment shown in the drawing, sixtransmitting antennas Tx and eight receiving antennas Rx are deployedalong separate curved lines. Horizontal intervals between thetransmitting antennas and horizontal intervals between the receivingantennas are values of 0 to 2 units, that is, the transmitting antennasand the receiving antennas are deployed at irregular horizontalintervals. Also, vertical intervals between the transmitting antennasand vertical intervals between the receiving antennas are values of 0 to1 unit, that is, the transmitting antennas and the receiving antennasare deployed more closely in the vertical direction than in thehorizontal direction but likewise at irregular intervals.

FIG. 3B shows a distribution of received beams which are receivedthrough the receiving antennas while the transmitting antennas aresequentially driven in the antenna arrangement according to theexemplary embodiment shown in FIG. 3A. Since intervals between thetransmitting and receiving antennas are greater in the horizontaldirection than in the vertical direction, the received beams aredistributed more widely in the horizontal direction than in the verticaldirection.

The distribution of received beams is the same as the distribution ofbeams received when the transmitting and receiving antennas physicallydeployed at the same positions are individually driven. Therefore, inthis specification, the arrangement of individual antennas which havethe same distribution of received beams as a case in which a pluralityof transmitting antennas and a plurality of receiving antennas includedin an arrangement are sequentially scanned is referred to as an“equivalent virtual antenna arrangement.”

As shown in FIG. 3B, when the plurality of transmitting and receivingantennas are deployed along curved lines at irregular intervals, somepositions in the distribution of received beams are empty, but there isa concentrated monitoring region. Also, as shown in FIG. 3B,distribution intervals between received beams in the received beamdistribution, that is, antenna distribution intervals of a virtualantenna arrangement, are less than half a received wavelength.Accordingly, it is possible to prevent generation of an undesirablegrating lobe.

FIG. 4A shows a physical arrangement of transmitting antennas andreceiving antennas according to another exemplary embodiment of thepresent invention. In the exemplary embodiment shown in the drawing, 12transmitting antennas Tx and 16 receiving antennas Rx are deployed alongseparate curved lines. Horizontal intervals between the transmittingantennas and horizontal intervals between the receiving antennas arevalues of 0 to 4 units, that is, the transmitting antennas and thereceiving antennas are deployed at irregular horizontal intervals. Also,vertical intervals between the transmitting antennas and verticalintervals between the receiving antennas are values of 0 to 1 unit, thatis, the transmitting antennas and the receiving antennas are deployedmore closely in the vertical direction than in the horizontal directionbut at irregular intervals likewise.

FIG. 4B shows the distribution of virtual antennas or the distributionof received beams which are received through the receiving antennaswhile the transmitting antennas are sequentially driven in the antennaarrangement according to the exemplary embodiment shown in FIG. 4A.Since intervals between the transmitting and receiving antennas aregreater in the horizontal direction than in the vertical direction, thereceived beams are distributed more widely in the horizontal directionthan in the vertical direction. When the 12 transmitting antennas andthe 16 receiving antennas are sequentially driven, it is possible toobtain the same effect as a case in which 192 virtual antennas arespatially deployed.

As shown in the exemplary embodiments shown in the drawings, a virtualantenna arrangement corresponding to a physical antenna arrangement maybe calculated by adding all patterns which are obtained by shiftingdriven physical transmitting antennas to the positions of drivenphysical receiving antennas. For this reason, even when the transmittingantennas or the receiving antennas are deployed at regular intervalsalong a straight line or a curved line and the receiving antennas or thetransmitting antennas are non-uniformly and linearly deployed, it ispossible to achieve spatially wide coverage proposed by the presentinvention.

[Description of FIG. 5 —Claim 1]

FIG. 5 is a block diagram showing a configuration of a radar apparatusaccording to an exemplary embodiment of the present invention. Accordingto an aspect, the radar apparatus includes a memory 900, a sensor signalprocessor 300, and a target position calculator 500. The memory 900stores antenna configuration related information. The antennaconfiguration related information is determined according to thearrangement of antennas. The antenna configuration related informationis determined according to the shape of a physical antenna arrangementand, more directly, according to an arrangement of virtual antennasderived from the physical antenna arrangement. According to an aspect,the antenna arrangement includes a plurality of transmitting antennasand a plurality of receiving antennas. The plurality of transmittingantennas and/or the plurality of receiving antennas are non-uniformlyand linearly deployed. In this specification, “antenna configurationrelated information” is defined as information which reflects a physicalstatic arrangement of a plurality of transmitting antennas and aplurality of receiving antennas. According to an additional aspect,“antenna configuration related information” may be determined accordingto a dynamic operation sequence of the plurality of transmittingantennas and the plurality of receiving antennas. Such antennaconfiguration related information may be information reflecting acalculation sequence of range and Doppler data among virtual antennas.

While sequentially driving the plurality of transmitting antennas, thesensor signal processor 300 calculates target range-Doppler dataaccording to virtual antennas from signals input from the receivingantenna arrangement. Here, range data denotes a radial distance to atarget, and Doppler data denotes a value related to radial speed. Forexample, when four transmitting antennas which are non-uniformly andlinearly deployed are (Tx1, Tx2, Tx3, Tx4) and six receiving antennaswhich are non-uniformly and linearly deployed are (Rx1, Rx2, Rx3, Rx4,Rx5, and Rx6), the sensor signal processor 300 according to an exemplaryembodiment of the present invention sends a radar signal at Tx1 firstand receives six signals at the receiving antennas Rx1, Rx2, Rx3, Rx4,Rx5, and Rx6 in the transmitting and receiving antenna arrangement.Subsequently, the sensor signal processor 300 sends a radar signal atTx2 and receives six signals at the receiving antennas Rx1, Rx2, Rx3,Rx4, Rx5, and Rx6. Subsequently, the sensor signal processor 300 sends aradar signal at Tx3 and receives six signals at the receiving antennasRx1, Rx2, Rx3, Rx4, Rx5, and Rx6. Subsequently, the sensor signalprocessor 300 sends a radar signal at Tx4 and receives six signals atthe receiving antennas Rx1, Rx2, Rx3, Rx4, Rx5, and Rx6, therebyfinishing one transmission and reception cycle.

Calculating target range-Doppler data from a received radar signal is awell-known method. FIG. 6 is a block diagram showing a configuration ofthe sensor signal processor 300 which processes a signal received by onevirtual antenna according to an exemplary embodiment of the presentinvention. As shown in the drawing, the sensor signal processor 300according to an exemplary embodiment of the present invention includes arange and Doppler processor 310 and a target selector 370. Whilesequentially driving the plurality of transmitting antennas, the rangeand Doppler processor 310 calculates range-Doppler data according tovirtual antennas from signals input through the plurality of receivingantennas.

The range and Doppler processor 310 may include a target rangecalculator 330 and a Doppler processor 350. The target range calculator330 calculates range data according to virtual antennas from the signalsinput through the receiving antennas. The target range calculator 330samples FMCW digital radar signals input through the antennas and storesthe FMCW digital radar signals in units of modulation periods, and aone-dimensional Fourier transformer 331 performs a Fouriertransformation and outputs M pieces of range data, that is, Fouriercoefficients.

The Doppler processor 350 calculates range-Doppler data according tovirtual antennas by processing the calculated range data. The Dopplerprocessor 350 stores N pieces of range data, which is M rangeindex-specific coefficient values output from the target rangecalculator 330, in a two-dimensional memory 353 in a row direction. Atwo-dimensional Fourier transformer 351 accesses the two-dimensionalmemory 353 in a column direction, which is a time-axis direction, andgenerates M pieces of range-Doppler data, which are L Fouriercoefficients, by performing Fourier transformations on N pieces of rangedata. The M×N pieces of data have range information in the row directionand have Doppler information in the column direction and are referred toas range-Doppler data. Row direction indices of the memory array arereferred to as range indices, and column direction indices are referredto as Doppler indices.

Subsequently, the target selector 370 selects a position of a valuewhich is highly likely to be a signal of the actual target from amongvalues 373 represented as (a range index, a Doppler index) using aconstant false alarm rate (CFAR) algorithm 371 and the like. Forexample, such signal processing is applied to each of all the virtualantennas shown in FIG. 3B or FIG. 4B. The target selector 370 providesonly selected pieces of data to the target position calculator 500 among(a range index, a Doppler index) pairs so that data processing may bereduced.

Referring back to FIG. 5 , according to an aspect, the target positioncalculator 500 calculates position data of a target from arrangementmapped data which is obtained by rearranging virtual antenna-specificrange-Doppler data output from the sensor signal processor 300 accordingto a two-dimensional arrangement of virtual antennas with reference tothe antenna configuration related information. The arrangement mappeddata denotes a computable data arrangement which has been rearranged sothat a target position may be calculated according to general radarsignal processing. According to an aspect, the arrangement mapped datamay denote data obtained by rearranging range-Doppler data of a targetin consideration of the arrangement of virtual antennas, that is, bymapping target range-Doppler data to the arrangement of virtualantennas, so that a target position may be calculated.

[Description of FIG. 7 —Detailed Position Calculation of Claims 4 and 5]

FIG. 7 is a block diagram showing a configuration of the target positioncalculator 500 according to an exemplary embodiment of the presentinvention. The target position calculator 500 according to an exemplaryembodiment of the present invention includes a data access controller510 and an angular position calculator 530. The data access controller510 rearranges selected virtual antenna-specific range-Doppler data 577of targets into target-specific arrangement mapped data according to atwo-dimensional arrangement of virtual antennas with reference toantenna configuration related information 571 and outputs thetarget-specific arrangement mapped data.

As shown in the drawing, a range-Doppler data set 573 is athree-dimensional data set in which M×L range-Doppler data is arrangedfor each of P virtual antennas. As shown in a square formed of a dottedline, the data access controller 510 extracts range-Doppler data whichhas been determined to be highly likely to be a target by the targetselector 370 of FIG. 6 , that is, pieces of data at colored positions inthe drawing, from M×L range-Doppler data on the basis of all of the Pvirtual antennas. A plurality of targets may be selected from therange-Doppler data set 573. The data access controller 510 rearrangesthe virtual antenna-specific range-Doppler data 577 into target-specificarrangement mapped data according to the two-dimensional arrangement ofvirtual antennas with reference to the antenna configuration relatedinformation 571 and outputs the target-specific arrangement mapped data.

The arrangement mapped data is data obtained by rearrangingrange-Doppler data which has been determined to be highly likely to be atarget in the range-Doppler data set 573 so that the rearrangedrange-Doppler data may be matched to a spatial arrangement of virtualantennas. In other words, in FIG. 7 , range-Doppler data 577 of onetarget in the range-Doppler data set 573 has been arranged in an arraysequence of virtual antennas determined according to a data processingstructure. However, the spatial arrangement of virtual antennas isnon-uniform and linear as shown in FIG. 8 .

FIG. 8 shows an exemplary arrangement of 192 virtual antennas achievedby sequentially driving 12 transmitting antennas and 16 receivingantennas. Such an arrangement of virtual antennas has been shown in FIG.3B as derived from the physical arrangement of FIG. 3A and FIG. 4B asderived from the physical arrangement of FIG. 4A. Virtual antennas arepositioned in colored cells. No virtual antennas are positioned in emptycells, and range-Doppler data corresponding to the empty cells is filledwith 0. Numbers recorded in the colored cells are orders or indices in az-axis, which is the virtual antenna direction, in the range-Dopplerdata set 573 of FIG. 7 . These orders are determined according to a dataprocessing structure. In other words, the orders are determinedaccording to in what sequence range-Doppler data generated forrespective virtual antennas by the target range calculator 330 and theDoppler processor 350 in the exemplary embodiment shown in FIG. 6 iscollected in a memory by the target selector 370. However, the spatialarrangement of virtual antennas is non-uniform and discrete as shown inFIG. 8 . Therefore, it is impossible to apply a general existing angularposition calculation method to data which is in the same state as theM×L range-Doppler data set 573 of FIG. 7 .

In the range-Doppler data set 573 of FIG. 7 , range-Doppler data of allthe 192 virtual antennas is stored in the z-axis direction in a sequenceaccording to such a data processing structure. However, it is necessaryto rearrange the 192 virtual antennas to actually have spatialdistribution as shown in FIG. 8 . The data access controller 510rearranges the range-Doppler data into arrangement mapped data accordingto targets in order of such a two-dimensional arrangement of virtualantennas with reference to the antenna configuration related information571 and outputs the arrangement mapped data.

Two exemplary embodiments are proposed to rearrange range-Doppler data577 of a specific target in the range-Doppler data set 573 intoarrangement mapped data.

According to an aspect, the data access controller 510 extracts datacorresponding to each address of the two-dimensionally arranged memoryarray of virtual antennas from selected range-Doppler data of a targetwhich is one-dimensionally arranged according to the virtual antennaswith reference to the antenna configuration related information 571 andstores the corresponding data. In a first exemplary embodiment, anoutput buffer of the data access controller 510 may have the length ofan azimuth direction or an elevation direction in the virtual antennaarrangement. The buffer may have one of two sizes which is determinedaccording to whether the angular position calculator 530 performs dataprocessing in the azimuth direction or elevation direction first. Forexample, in FIG. 8 , a kth azimuth direction row extracted from theupper virtual antenna arrangement is shown at the lower end. This rowhas a length of 128, and in this exemplary embodiment, the output bufferof the data access controller 510 may have a size of 128. The dataaccess controller 510 outputs range-Doppler data corresponding to anazimuth direction row requested by the angular position calculator 530in range-Doppler data 577 of one target extracted from the range-Dopplerdata set 573 of FIG. 7 , that is, 128 pieces of data which arerearranged in order of (0, 0, 0, 0, 0, 8^(th), 38^(th), 0, 0, 53^(rd), .. . ) in the example shown at the lower end of FIG. 8 , to the outputbuffer. When data processing of the azimuth direction row adopts aparallel structure in which data of a plurality of rows issimultaneously processed, the output buffer may be increased as manytimes as the number of rows processed in parallel. Also, when data of aplurality of targets is simultaneously processed, as many data accesscontrollers 510 and angular position calculators as the number oftargets simultaneously processed may be provided.

According to another aspect, the antenna configuration relatedinformation 571 may include information on the index of a virtualantenna of a corresponding position at each address of a memory arrayhaving the same size as the two-dimensional arrangement of virtualantennas. For example, the map shown in the upper side of FIG. 8 may bean example of the antenna configuration related information 571. Amemory in which the antenna configuration related information 571 isstored is a memory array having the same size as the two-dimensionalarrangement of virtual antennas, that is, a size of 128×128 in thiscase. At respective addresses of the memory array, indices of virtualantennas at positions corresponding to the addresses are recorded. Inthe exemplary embodiment shown in the drawing, cells which have novirtual antenna at the corresponding positions are filled with 0. Memoryaddresses of such “null” positions may be filled with a specialcharacter or a distinguishable number. The data access controller 510extracts spatial arrangement information of virtual antennas of a partrequested by the angular position calculator 530 by accessing thecorresponding part of the memory in which the antenna configurationrelated information 571 is stored and records, in the output buffer,range-Doppler data acquired by accessing range-Doppler data 577 of onetarget with the index information. The data recorded in the outputbuffer may be arrangement mapped data.

The angular position calculator 530 calculates an angular position ofeach target from arrangement mapped data of the corresponding target.The angular position calculator 530 may also calculate an angularposition of a corresponding target by processing the rearrangedarrangement mapped data in the same manner as radar signals to generalantennas which are uniformly and linearly deployed.

[Description of FIG. 9 —Detailed Position Calculation of Claims 6 and 7]

FIG. 9 is a block diagram showing a configuration of the target positioncalculator 500 according to another exemplary embodiment of the presentinvention. According to another aspect, the data access controller 510sequentially extracts selected range-Doppler data of a target which isone-dimensionally arranged according to virtual antennas and stores theextracted range-Doppler data at corresponding addresses of thetwo-dimensionally arranged memory array of virtual antennas withreference to the antenna configuration related information 571.According to an additional aspect, the antenna configuration relatedinformation 571 may be information in which corresponding addresses ofthe spatial arrangement of virtual antennas are listed in the sequenceof the virtual antennas in the virtual antenna-specific range-Dopplerdata.

In this exemplary embodiment, the data access controller 510 may includea data rearranger 511. The data rearranger 511 rearranges range-Dopplerdata 577 of one target extracted from the range-Doppler data set 573into arrangement mapped data 513 with reference to the antennaconfiguration related information 571 according to the spatialarrangement of virtual antennas and stores the arrangement mapped data513. The angular position calculator 530 may calculate an angularposition by processing the arrangement mapped data 513 stored in amemory in the same manner as radar signals to general antennas which areuniformly and linearly deployed.

As shown in the drawing, the range-Doppler data 573 is three-dimensionaldata set in which M×L range-Doppler data is arranged for each of Pvirtual antennas. As shown in a square formed of a dotted line, piecesof data at colored positions are extracted from M×L range-Doppler dataon the basis of all of the P virtual antennas. The data rearranger 511extracts specific range-Doppler data from the range-Doppler data set 573on the basis of all the virtual antennas, rearranges the extractedspecific range-Doppler data with reference to the antenna configurationrelated information 571 according to the positions of the virtualantennas, and stores the rearranged specific range-Doppler data in thememory as the arrangement mapped data 513.

According to an additional aspect, the antenna configuration relatedinformation 571 may be information in which corresponding addresses ofthe spatial arrangement of virtual antennas are listed in the sequenceof the virtual antennas in the virtual antenna-specific range-Dopplerdata. FIG. 10 is a diagram illustrating another example of antennaconfiguration related information. In the exemplary embodiment shown inthe drawing, when the left uppermost corner is (0, 0), the antennaconfiguration related information may be the following array accesssequence information:

(5, 1), (4, 2). (1, 3), (5, 3), (3, 4), (2, 5), (5, 4), (4, 5), . . . .

The data rearranger 511 extracts specific range-Doppler data from athree-dimensional range-Doppler data set in a virtual antenna sequenceand sequentially records the specific range-Doppler data at a positionof the arrangement mapped data 513 according to the antennaconfiguration related information described in the above exemplaryembodiment. In this exemplary embodiment, the memory is accessed only asmany times as the number of the virtual antennas, and thus it ispossible to reduce the number of memory access times compared to theexemplary embodiment described above with reference to FIGS. 7 and 8 .

[Description of FIG. 11 —Angular Position Calculator]

FIG. 11 is a block diagram showing a configuration of an angularposition calculator according to an exemplary embodiment of the presentinvention.

The angular position calculator 530 according to an exemplary embodimentof the present invention calculates angular positions for respectivepairs of range-Doppler data from the rearranged arrangement mapped data.Since pieces of data are aligned by the data access controller 510, theangular position calculator 530 may have the same configuration forangular position calculation as in a general radar having uniformly andlinearly deployed antennas. According to an exemplary embodiment, theangular position calculator 530 includes an azimuthal Fouriertransformer 531, a buffer memory 533, an elevation Fourier transformer535, and a fine estimator 537. Each of Fourier transformers in theazimuthal Fourier transformer 531 receives data of one row obtained byextracting the arrangement mapped data output from the data accesscontroller 510 in an azimuth direction, performs a Fouriertransformation on the data, and stores the Fourier-transformed data inthe buffer memory 533 in a row direction. Each of Fourier transformersin the elevation Fourier transformer 535 receives the data, which hasbeen output from the azimuthal Fourier transformer 531 and stored in thebuffer memory 533, column by column, performs a Fourier transformationon the data, and outputs the Fourier-transformed data. The fineestimator 537 projects an input Fourier transformation coefficient arrayto a beam space, calculates an azimuth and an elevation of a targetthrough fine estimation, and outputs the azimuth and the elevation.

Referring back to FIG. 5 , the radar apparatus may further include anantenna arrangement input section 230 according to an additional aspect.The antenna arrangement input section 230 receives and storesinformation related to a new antenna configuration in the memory 900.When the arrangement of physical antennas is changed, a new antenna isinstalled, or the radar apparatus is initialized for the first time,antenna configuration related information may be input.

According to an additional aspect, the radar apparatus may furtherinclude an antenna operation mode selector 210. The antenna operationmode selector 210 may apply one of multiple antenna configurationrelated information sets to the radar apparatus according to anoperation selection instruction. As an example, the operation selectioninstruction may be an input of a user. As another example, the operationselection instruction may be an operation selection instruction based ona determination of a controller. Multiple antenna configuration relatedinformation sets are provided in the memory 900. Although a physicalantenna arrangement is fixed, it is possible to control characteristicsof the radar by selectively driving only some of the antennas. As anexample, it is possible to select an operation mode for rapidlysearching for a target with a low resolution by reducing the number ofantennas while maintaining a similar arrangement. As another example, itis possible to select an operation mode in which sensitivity to aspecific direction is increased by selectively driving only antennas ofthe specific direction among the antennas. For example, it is possibleto selectively apply a horizontal running mode in which horizontalsensitivity is high and a vertical running mode in which verticalsensitivity is high.

Exemplary embodiments of the present invention have been described abovewith reference to the accompanying drawings, centering on an apparatus.However, radar signals may be processed by a computer program includinginstructions which are executed by computing elements such as a digitalsignal processor or a general-use processor. Some or all of theinstructions may be implemented by dedicated hardware or a gate array.

According to the present invention, it is possible to provide a radarwhich has wide coverage due to the arrangement of a plurality ofreceiving antennas which are non-uniformly and linearly deployed. Also,radar signals received from the non-uniformly and linearly deployedantennas may be processed using a processing technique for radar signalsreceived from uniformly and linearly deployed antennas. Further, a radarphysically having one antenna arrangement may provide multiple differentcharacteristics.

A number of examples have been described above. Nevertheless, it will beunderstood that various modifications may be made. For example, suitableresults may be achieved if the described techniques are performed in adifferent order and/or if components in a described system,architecture, device, or circuit are combined in a different mannerand/or replaced or supplemented by other components or theirequivalents. Accordingly, other implementations are within the scope ofthe following claims.

What is claimed is:
 1. A radar apparatus comprising: an antennaarrangement including a plurality of transmitting antennas and aplurality of receiving antennas, at least one kind of which arenon-uniformly and linearly deployed; a sensor signal processor includinga range and Doppler processor configured to calculate range-Doppler datafor each of virtual antennas from signals input through the plurality ofreceiving antennas while sequentially driving the plurality oftransmitting antennas; and a target position calculator configured tocalculate position data of a target from arrangement mapped dataobtained by rearranging the range-Doppler data calculated by the sensorsignal processor according to a two-dimensional arrangement of thevirtual antennas, wherein the target position calculator includes: adata access controller configured to rearrange the range-Doppler data ofthe targets into target-specific arrangement mapped data according to atwo-dimensional spatial arrangement of the virtual antennas and outputthe target-specific arrangement mapped data; and an angular positioncalculator configured to calculate angular positions of the targets fromthe target-specific arrangement mapped data.
 2. The radar apparatus ofclaim 1, wherein the sensor signal processor further includes a targetselector configured to select and output antenna-specific range-Dopplerdata of one or more targets which are highly likely to be the targetfrom the calculated range-Doppler data.
 3. The radar apparatus of claim1, wherein the data access controller extracts data, which correspondsto each address of a two-dimensionally arranged memory array of thevirtual antennas from the range-Doppler data of the targets, which isone-dimensionally arranged according to the virtual antennas withreference to antenna configuration related information, and stores thecorresponding data.
 4. The radar apparatus of claim 3, wherein theantenna configuration related information includes information on anindex of a virtual antenna of a corresponding position at each addressof the memory array having a size identical to a size of thetwo-dimensional arrangement of the virtual antennas.
 5. The radarapparatus of claim 1, wherein the data access controller sequentiallyextracts the range-Doppler data of the targets which isone-dimensionally arranged according to the virtual antennas and storesthe extracted range-Doppler data at corresponding addresses of atwo-dimensionally arranged memory array of the virtual antennas withreference to antenna configuration related information.
 6. The radarapparatus of claim 5, wherein the antenna configuration relatedinformation includes information in which corresponding addresses of thespatial arrangement of the virtual antennas are listed in a sequence ofthe virtual antennas in the virtual antenna-specific range-Doppler data.7. The radar apparatus of claim 1, wherein the angular positioncalculator includes: an azimuthal Fourier transformer configured toperform a Fourier transformation on the arrangement mapped data in unitsof rows in an azimuth direction and output Fourier coefficients; anelevation Fourier transformer configured to access the Fouriercoefficients output from the azimuthal Fourier transformer in a columndirection, perform a Fourier transformation on the Fourier coefficientsin units of columns, and output Fourier-transformed data; and a fineestimator configured to project the output of the elevation Fouriertransformer to a beam space, calculate azimuths and elevations of thetargets through fine estimation, and output the azimuths and theelevations.
 8. The radar apparatus of claim 5, further comprising anantenna arrangement input section configured to receive and storeinformation related to a new antenna configuration.
 9. The radarapparatus of claim 5, further comprising a radar operation mode selectorconfigured to apply one of multiple antenna configuration relatedinformation sets according to an operation selection instruction.
 10. Aradar signal processing method implemented by a computer programincluding instructions executed by a computing element of a radarconnected to an antenna arrangement including a plurality oftransmitting antennas and a plurality of receiving antennas, at leastone kind of which are non-uniformly and linearly deployed, the methodcomprising: a sensor signal processing operation including a range andDoppler processing operation of calculating range-Doppler data for eachof virtual antennas from signals input through the plurality ofreceiving antennas while sequentially driving the plurality oftransmitting antennas; and a target position calculation operation ofcalculating position data of a target from arrangement mapped dataobtained by rearranging the range-Doppler data calculated in the sensorsignal processing operation according to a two-dimensional arrangementof the virtual antennas, wherein the target position calculationoperation includes: a data access control operation of rearranging therange-Doppler data of the targets into target-specific arrangementmapped data according to a two-dimensional arrangement of the virtualantennas and outputting the target-specific arrangement mapped data; andan angular position calculation operation of calculating an angularposition for each piece of the range-doppler data from the arrangementmapped data.
 11. The radar signal processing method of claim 10, whereinthe sensor signal processing operation further includes a targetselecting operation of selecting and outputting antenna-specificrange-Doppler data of one or more targets which are highly likely to bethe target in the calculated virtual antenna-specific range-Dopplerdata.
 12. The radar signal processing method of claim 10, wherein thedata access control operation includes extracting data corresponding toeach address of a two-dimensionally arranged memory array of the virtualantennas from the range-Doppler data of the targets, which isone-dimensionally arranged according to the virtual antennas withreference to antenna configuration related information, and storing thecorresponding data.
 13. The radar signal processing method of claim 12,wherein the antenna configuration related information includesinformation on an index of a virtual antenna of a corresponding positionat each address of the memory array having a size identical to a size ofthe two-dimensional arrangement of the virtual antennas.
 14. The radarsignal processing method of claim 10, wherein the data access controloperation includes sequentially extracting the range-Doppler data of thetargets which is one-dimensionally arranged according to the virtualantennas and storing the extracted range-Doppler data at correspondingaddresses of a two-dimensionally arranged memory array of the virtualantennas with reference to antenna configuration related information.15. The radar signal processing method of claim 14, wherein the antennaconfiguration related information includes information in whichcorresponding addresses of the spatial arrangement of the virtualantennas are listed in a sequence of the virtual antennas in the virtualantenna-specific range-Doppler data.
 16. The radar signal processingmethod of claim 10, wherein the angular position calculation operationincludes: an azimuthal Fourier transformation operation of performing aFourier transformation on the arrangement mapped data in units of rowsin an azimuth direction and outputting Fourier coefficients; anelevation Fourier transformation operation of accessing the Fouriercoefficients output from the azimuthal Fourier transformation operationin a column direction, performing a Fourier transformation on theFourier coefficients in units of columns, and outputtingFourier-transformed data; and a fine estimation operation of projectingthe output of the elevation Fourier transformation operation to a beamspace, calculating azimuths and elevations of the targets through fineestimation, and outputting the azimuths and the elevations.
 17. Theradar signal processing method of claim 14, further comprising anantenna arrangement input operation of receiving and storing informationrelated to a new antenna configuration.
 18. The radar signal processingmethod of claim 14, further comprising a radar operation mode selectingoperation of applying one of multiple antenna configuration relatedinformation sets according to an operation selection instruction.